Hydraulic power lines for industrial truck



July 10, 1956 c. s. SCHROEDER 2,7

HYDRAULIC POWER LINES FOR INDUSTRIAL TRUCK Filed July 13, 1953 2Sheets-Sheet 1 hl h 2 I 1 l as 6 INVENTCR BYMM ATTORNEY July 10, 1956 cs, SCHRQEDER 2,754,018

HYDRAULIC POWER LINES FOR INDUSTRIAL TRUCK Filed July 13, 1953 2Sheets-Sheet 2 fla -J.

2 i 45 34 25 I: I I I I 47 I I I I I I I I Z] 46 I T I no I L OE CA'I;FEI A G E i I I I 50 51 37 I I I I l I Z I I 49 E ROTATING 42"/mslglgl l 2s 4 I I I I I I 5 I I I I I I I I I I I I I I I I IATTORNEY United States Patent HYDRAULIC PGWER LINES FOR INDUSTRIAL TRUCKCharles S. Schroeder, Philadelphia, Pa., assignor to The Yale & TownsManufacturing Company, Stamford, Conn, a corporation of ConnecticutApplication July 13, 1953, Serial No. 367,508

9 Claims. (Cl. 214-652) This invention relates to industrial lifttrucks. More particularly, my invention relates to hydraulic means foroperating load manipulating devices on the lifting carriage of trucks ofthis class.

It is quite usual to provide upon the lifting carriage, in trucks ofthis class, a hydraulic motor or ram for operating a load manipulatingdevice, with the motor or ram powered by a source of fluid pressure onthe main frame of the truck. To convey the fluid pressure to the ram inall vertical positions of the carriage relatively to the truck, flexiblehydraulic lines extend from the main frame to the carriage. A manuallyoperated valve on the truck controls the fluid in the hydraulic lines,and thereby enables the operator to control the load manipulatingdevice.

It is frequently desired to utilize two or more load manipulatingdevices on the lifting carriage. At least one motor or ram is requiredfor operating each load manipulating device, and, to enable the operatorto have individual control over all of these motors or rams, the priorart utilizes separate flexible lines extending from the main frame tothe carriage for each ram or motor. Obviously, this means that for afairly complex series of load manipulating devices, the prior artrequires a complex array of flexible hose.

I have now contributed by my invention an extremely novel hydraulicsystem through which I provide complete and individual control over theindividual rams or motors for several load manipulating devices whileutilizing. only the same number of flexible hydraulic lines required foroperating one motor or ram.

As one important feature of my invention, I direct the fluid pressurethrough a flexible line to the lifting, carriage, with valve means atthe carriage then directing the pressure to the rams individually inaccordance with the positioning of the valve'means. Preferably, withthis arrangement I utilize but a single manually operated valve on thetruck to control several load manipulating devices on the carriage. Whenthe rams or motors are of the type that discharges exhaust fluid whilebeing actuated by the fluid under pressure, I utilize a pair of theflexible lines extending between the truck and the carriage, with themanually operated valve allowing the fluid to return through one ofthese lines to the source on the truck while the fluid pressure isapplied through the other line. If the rams are of the type thatdischarge fluid only when moving in a reverse direction, it is notnecessary to provide for fluid flow simultaneously both directionsbetween the truck and carriage, and I can utilize merely a singleflexible line. In no case, however; do I require more than a pair of.flexible hydraulic lin'e's', because my invention enables me to directfluid inb'o'th directions between the flexible lines and the individualrants or motors.

As more detailed feature of my invention, I provide means upon the mainframe of the truck for actuating the valve means on the carriage.Through this arrangement, in conjunction with a manually operated valve:on the truck, the operator can very easily control the individual loadmanipulating devices. More particularly, I prefer to utilize solenoidsfor positioning the valve means, with switch means upon the truck foractuating the solenoids.

I have thus outlined rather broadly the more important features of myinvention in order that the detailed description thereof that followsmay be better understood, and in order that my c'on'tribution'to the artmay be better appreciated. There are, of course, additional features ofmy invention that will be described hereinafter and which will form thesubject of the claims appended hereto. Those skilled in the art willappreciate that the conception on which my disclosure is based mayreadily be utilized as a basis for the designingof other structures forcarrying out the several purposes of my invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions as do not depart from the spirit and scope of myinvention, in order to prevent the appropriation of my invention bythose skilled in the art.

Referring now to the drawings:

Fig. 1 is a side view of a lift truck vention.

Fig. 2 is a plan view of the truck.

Fig. 3 is a diagram illustrating my novel power line arrangement. a

For the purpose of describing my invention, I show in Figs. 1 and 2several load manipulating devices mounted upon a lifting carriage IIIthat moves vertically on uprights 11 of an industrial truck T. Theparticular details of the truck T are not important to an understandingof my invention, and it is merely necessary to know that the carriage 10moves relatively to the truck.

By way of example, I have illustrated one of the load manipulatingdevices as a load clamping means having clamping arms 12, 13' on a basemember 14. The arm 13 is mounted on the base member 14 through apivot 15for movement relatively to the arm 12, and a hydraulic ram 16 at therear end of the arm 13 is adapted to move this arm in opposed directionson its pivot 15 for clamping and releasing a load between the arms.

As an example of a further manipulating device, the base member 14 ismounted to rotate on the longitudinal axis of the truck, relatively to amember I7 on't-he carriage 10. This rotation is effected throughahydraulic motor' or ram 18 on the member 17, and thereby a load clampedbetweenthe arms 12, 13 can be inverted or tilted to a desired angle.

Still further, I show a hydraulic ram 19 on the carriage 10 that isadapted to shift the member 17 in a transverse direction relatively tothe truck. Through this arrangement, the clamping arms 12, 13 can beshifted in a sidewise direction to be brought into proper alignment witha load to be picked up, or to shift a load already clamped between thearuis.

The load manipulating devices as I have described them are conventional,and it will be understood that my invention is not limited to anyparticular manipulating devices. My invention is directed rather towardthe novel hydraulic system whereby I operate the load manipulatingdevices, and I shall now proceed to describe this hydraulic system.

Extending between the main frame of the truck T and the lifting carriage10 I provide a pair of flexible hydraulic lines 20, 21 that are shown inFigs; 1 and 2-, but best seen in their relation to the hydraulic systemin- Fig. 3. Upon the main frame of the truck, the hydraulic lines 20, 21are connected to a manually operated valve 22, and this valve isconnected in turn to a source of fluid pressure S through a supply line23" and a return line 24; The manually operated valve 22 has passages25* whereby the supply and return lines 235, 24 can be placed incommunication with the flexible lines 20', 21,

embodying my in- 3 with rotation of the valve reversing the relationbetween the lines. Thus, in the position of the valve shown in Fig. 3,the supply line 23 is connected by a passage 25 with the flexible line21 whereby the line 21 also is a supply line, and the flexible line 20is a return line because it is connected through the other passage 25with the return line 24. When the passages 25 are placed in their dottedline positions by rotation of the valve 22, the flexible line 20 is asupply line, while the line 21 is a return line. The valve 22 may, ofcourse, be rotated to an intermediate holding position in which thepassages 25 do not connect any of the hydraulic lines.

To serve as the valve means upon the lifting carriage, I prefer toutilize a valve 26 having a piston 27, and a second similar valve 28having a piston 29. The piston 27 of the first valve 26 has twoperipheral recesses 30, 31, and each flexible line 20, 21 is incommunication with one of these recesses at all times. Also incommunication with the recesses 30, 31, in the normal position of thepiston 27 are a pair of lines or passages 32, 33 that lead to the secondvalve 28, thereby transmitting to the second valve fluid pressure fromone of the flexible lines 20, 21, and also returning fluid from thevalve 28 to the other flexible line 20 or 21., I shall describe fullythe action of the valve 28, but it is first to be noted that, when thevalve 26 is actuated, the piston 27 moves in such a way as to cut offcommunication between the flexible lines 20, 21 and the passages 32, 33,with the recesses 30, 31 then placing the lines 20, 21 in communicationwith lines 34, 35 that lead to opposed ends of the rotating ram 18. Uponactuation of the valves 26, therefore, fluid pressure from the supplyline 23 can be applied to either end of the rotating ram 18, dependingupon the position of the manually operated valve 22, with the fluiddischarged from the opposed end of the ram moving simultaneously to thereturn line 24.

Returning now to the second valve 28, it will be observed that thepiston 29 has peripheral recesses 36, 37 that normally place thepassages 32, 33 in communication with lines 38, 39 leading to opposedends of the clamp ram 16. By this arrangement, when the valves 26 and 28are both in normal position, the fluid pressure is applied to either endof the clamp ram 16 through manipulation of the manually operated valve22, while the fluid discharged from the opposed end of the ram returnsto the line 24.

I utilize the second valve 28 also to direct fluid relatively to theshift ram 19, and for this purpose I provide hydraulic lines 40, 41between the valve 28 and opposed ends of the ram 19. The arrangement issuch that, when the valve 28 is actuated, the piston 29 cuts olfcommunication between the passages 32, 33 and the lines 38, 39, and therecesses 36, 37 in the piston place the passages 32, 33 in communicationwith the lines 40, 41. Therefore, when the second valve 28 is actuatedand the first valve 26 is not actuated, the shift ram 19 can be operatedin either direction under the full control of the manually operatedvalve 22.

I have not thus far described a particular means for actuating thevalves 26 and 28 on the lifting carriage, but I do prefer to utilizeelectrical means for this purpose. Thus, the valves 26, 28 are of thetype having a spring 42 pressing the piston to a normal position, with asolenoid 43 that when energized moves the piston to actuated position.Upon the main frame of the truck T, in a position convenient to theoperator, I mount suitable switch means that I show by way of example asa pair of push button switches 44, 45. The switch 44 is connected to abattery 46 on the truck by a wire 47, and when pressed places thesolenoid 43 of the first valve 26 in circuit with the battery throughwires 48, 49. The push button 45 is adapted to place the solenoid of thesecond valve 28 in circuit with the battery 46 through the wire 47 andwires 50 and 51, the wire 51 being connected to the battery 46 throughthe wire 49. Preferably, the wires 48, 49, and 50 are parts of a cablethat extends between the main frame of the truck T and the liftingcarriage 10, as will be understood by those skilled in the art.

It may be well to review now the operation of my extremely novelhydraulic system. Normally the valves 26 and 28 are in their unactuatedpositions as shown in Fig. 3, with the flexible lines 20, 21 incommunication through these valves with the lines 38, 39, so that theclamp ram 16 can be operated merely through movement of the manuallyoperated valve 22. Therefore, if the truck T is maneuvered to bring theclamping arms 12, 13, into position at opposed sides of a load to belifted, movement of the valve 22 will effect clamping of the load, andwill release the load without requiring any additional controloperation.

If we assume now that it is desired to rotate the load clamped betweenthe arms 12, 13 after it has been lifted on the carriage 10, theoperator will first press the push button 44. This action will actuatethe valve 26, thereby cutting off communication between the flexiblelines 20, 21 and the second valve 28, and placing these lines incommunication with the rotating ram or motor 18 through the lines 34,35. If the operator now manipulates the valve 22 on the truck whileholding the push button 44 depressed, the fluid pressure will bedirected to the ram or motor 18 to rotate the load with the direction ofrotation determined by valve 22.

In those circumstances in which it is desired to shift the clamping arms12, 13 transversely, first the push button 45 will be depressed Whileleaving the push button 44 in normal position, thereby actuating onlythe second valve 28. The flexible lines 20, 21 are now in communicationwith the second valve 28, and through this valve with the shift ram 19.The operator will now manipulate the valve 22 to direct the fluidpressure to either end of the ram 19, thus shifting the arms 12, 13sidcwise in either direction.

I believe that those skilled in the art will now understand theextremely novel construction whereby I utilize one pair of hydrauliclines to accomplish the individual operation of several loadmanipulating devices on the lift ing carriage of an industrial truck,and that the very considerable value of my contribution will be fullyappreciated.

I now claim:

1. In a combination of the class described, an industrial truck having amain frame, a lifting carriage moving vertically on said main frame, atleast two load manipulating devices on said lifting carriage, a separatehydraulic motor for each of said load manipulating devices, a source offluid pressure on said main frame, a flexible hydraulic line throughwhich fluid flows between said fluid source and said carriage in allvertical positions of the carriage relatively to the main frame, asecond flexible hydraulic line through which fluid flows from saidcarriage in all vertical positions thereof back to said fluid source,hydraulic lines on the carriage in communication with said hydraulicmotors, selector valve means on said carriage between the flexiblehydraulic lines and said lines on the carriage, and means on said mainframe for actuating the selector valve means whereby to direct the fluidto and from each of the motors for said load manipulating devicesindividually.

2. In a combination of the class described, an industrial truck having amain frame, a lifting carriage moving vertically on said main farme, atleast two load manipulating devices on said lifting carriage, a separatehydraulic motor for each of said load manipulating devices, a source offluid pressure on said main frame, a flexible hydraulic line throughwhich fluid flows between said fluid source and said carriage in allvertical positions of the carriage relatively to the main frame, asecond flexible hydraulic line through which fluid flows from saidcarriage in all vertical positions thereof back to said fluid source,hydraulic lines. onthe. carriage in communication with said. hydraulicmotors, selector valve means on: the lifting carriage between the.flexible hydraulic lines and the lines on the carriage,.means.forpositioning the selector valve means whereby to direct the fluid to andfrom each of the hydraulic motors individually, and a. manually operatedvalve on said main frame controlling the flow of fluid in opposeddirections in said flexible hydraulic lines whereby to operateparticular load manipulating devices in accordance with the positioningof said selector valve means.

3. In a combination of the class described, an industrial truck having amain frame, a lifting carriage moving vertically on said main frame, atleast two load manipulating devices on said lifting carriage, a separatehydraulic motor for each of said load manipulating devices, a source offluid pressure on said main frame, a flexible hydraulic line throughwhich fluid flows between said fluid source and said carriage in allvertical positions .of the carriage relatively to the main frame, asecond flexible hydraulic line through which fluid flows from saidcarriage in all vertical positions thereof back to said fluid source,hydraulic lines on the carriage in communication with said hydraulicmotors, selector valve means on said carriage between the flexiblehydraulic lines and said lines on the carriage, electrical means on thelifting carriage for positioning said selector valve means whereby todirect the fluid to a particular hydraulic motor individually, and meanson the main frame for actuating said electrical means.

4. In a combination of the class described, an industrial truck having amain frame, a lifting carriage moving vertically on said main frame, aplurality of load manipulating devices on said lifting carriage, ahydraulic ram on said carriage for each of said load manipulatingdevices, a source of fluid pressure on said main frame, a pair ofhydraulic lines extending between said source and said carriage forcarrying fluid under pressure to said carriage and back to said source,a manually operated valve on said main frame for controlling thedirection of the flow of fluid in said pair of hydraulic lines, valvemeans on the carriage in communication with said pair of hydrauliclines, carriage supported hydraulic lines in communication with saidvalve means on said carriage to form a fluid circuit for the supply andreturn of fluid to each of said rams, and means positioning said valvemeans on said carriage in predetermined relation to said manuallyoperated valve to direct with said manually operated valve the fluidrelatively to each of said rams whereby to operate selectedcorresponding load manipulating devices in opposed directions.

5. In a combination of the class described, an industrial truck having amain frame, a lifting carriage moving vertically on said main frame, aplurality of load manipulating devices on said lifting carriage, ahydraulic ram on said carriage for each of said load manipulatingdevices, a source of fluid pressure on said main frame, a pair ofhydraulic lines extending between said source and said carriage forcarrying fluid under pressure to said carriage and back to said source,a manually operated valve on said main frame for controlling thedirection of the flow of fluid in said pair of hydraulic lines, valvemeans on the carriage in communication with said pair of hydrauliclines, carriage supported hydraulic lines in communication with saidvalve means on said carriage to form a fluid circuit for the supply andreturn of fluid to each of said rams, solenoid means on said carriagefor positioning said valve means to direct the fluid relatively to eachof said rams, and switch means on said main frame for actuating saidsolenoid means to effect with said manually operated valve theindividual operation of selected load manipulating devices.

6. In a combination of the class described, an industrial truck having amain frame, a lifting carriage moving vertically on said main frame, atleast two load manipulating device'sv on saidliftihg carriage, ahydraulic rant on said: carriage for each of said load: manipulatingdevices, a source of fluid pressure on said main: frame, a pair ofhydraulic lines extending between said source and said carriage. forcarrying fluid-under pressure to said carriage and back to said; source;in one direction or the other, valve means on the carriage incommunication with said pair of hydraulic lines and with each of saidrams, manual means on said main frame of the truck for directing theflow of fluid in opposed directions in said hydraulic lines, and meanson said main frame for actuating said valve means in combination withsaid manual means to direct the fluid pressure to one side or the otherof each of said rams whereby to control the operation of said loadmanipulating devices.

7. ln a combination of the class described, an industrial truck having amain frame, a lifting carriage moving vertically on said main frame, atleast two load manipulating devices on said lifting carriage, a separatehydraulic motor on said lifting carriage for each of said loadmanipulating devices, hydraulic valve means on said carriage forcontrolling each of said hydraulic motors, a source of hydraulicpressure on said main frame, a flexible hydraulic line in communicationwith said source on the main frame and extending from said main frame tosaid valve means on the carriage for supplying fluid through said valvemeans to all of said hydraulic motors in all vertical positions to whichthe load manipulating devices move with the carriage, and additionalmeans on said main frame extending to said valve means on said carriagefor positioning said valve means whereby to direct the fluid from theflexible hydraulic line to one or another of said motors for operatingsaid load manipulating devices individually.

8. In a combination of the class described, an industrial truck having amain frame, a lifting carriage moving vertically on said main frame, atleast two load manipulating devices on said lifting carriage, a separatehydraulic motor on said lifting carriage for each of said loadmanipulating devices, selector valve means on said carriage, hydrauliclines through which said valve means are in communication with saidhydraulic motors on the carriage, a source of hydraulic pressure on saidmain frame, a flexible hydraulic line in communication with said sourceon the main frame and extending to the selector valve means on thecarriage for supplying fluid through said valve means and lines to allof said hydraulic motors in all vertical positions to which the loadmanipulating devices move with the carriage, additional means on saidmain frame extending to the selector valve means on the carriage forpositioning said valve means to direct the fluid from the flexiblehydraulic line to one or another of said motors, and a manually operatedvalve on the main frame controlling the flow of fluid in said flexiblehydraulic line whereby to operate individually the load manipulatingdevices on the carriage in accordance with the positioning of saidselector valve means.

9. In a combination of the class described, an industrial truck having amain frame, a lifting carriage moving vertically on said main frame, atleast two load manipulating devices on said lifting carriage, a separatehydraulic ram on said lifting carriage for each of said loadmanipulating devices, selector valve means on said carriage, hydrauliclines through which said selector valve means are in communication witheach of said hydraulic rams, a source of hydraulic pressure on said mainframe, a flexible hydraulic line extending from the main frame to theselector valve means on the carriage for supplying fluid from saidsource to all of said hydraulic rams in all vertical positions to whichthe load manipulating devices move with the carriage, electrical meanson the carriage for positioning said selector valve means to direct thefluid through the lines on the carriage to the hydraulic ramsindividually, switch means on the main frame for actuating saidelectrical means, and a manually operated valve on the main framecontrolling the flow of fluid in References Cited in the file of thispatent UNITED STATES PATENTS Foster Feb. 7 1939 8 Twyman June 24, 1941Jeffrey Nov. 23, 1943 Fitch July 31, 1945 Glenn Nov. 20, 1951 TurnerJune 3, 1952 Sherrifi Aug. 4, 1953

